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Get Higher Quality Survey Data By Avoiding Overlapping Ranges

When designing and distributing a questionnaire, you should do everything in your power to ensure that you end up with informative, actionable survey data as a result.

In order to accomplish this, it's essential to keep the following best practices in mind.

How to Ensure That You're Receiving Quality Survey Data

When crafting a multiple-choice question with the goal of receiving actionable survey data, the answer options must be:

Mutually exclusive, and

Exhaustive

In other words the choices should not overlap and they should cover all possible answers to the question.

This seems straightforward enough, but that’s not always the case.

Let’s look at a couple of examples.

Example 1. How long have you worked at your current job?

Less than one year

1-2 years

3-4 years

5-6 years

More than 6 years

Don’t know/Not sure

The choices in this example are certainly mutually exclusive — there is no overlap — but they are not exhaustive. Not all possible answers are covered. Those that have been at their job between 2 and 3 years or between 4 and 5 years don’t have a choice to select.

This means that we would receive low quality survey data from this question.

A better set of choices would be:

Less than one year

1-2 years

2-4 years

4-6 years

More than 6 years

Don’t know/Not sure

This set of choices is exhaustive and, for the most part, mutually exclusive. We can certainly live with the small chances associated with someone having worked at their job for exactly 2 years or exactly 4 years.

Example 2. How many different office locations are there at your company?

One

2-4

4-8

8-12

More than 12

Don’t know

The choices in this example are exhaustive but not mutually exclusive. 4 and 8 are contained in each of two different choices. Again, we would end up with inactionable survey data from this question.

A better set of choices would be:

One

2-4

5-8

9-12

More than 12

Don’t know

This set of choices is exhaustive and mutually exclusive.

These two examples lead us to the following general guidelines:

For interval data, the choices should overlap at the end points

For count data, the choices should not overlap

Here are two more examples that illustrate these guidelines.

Example 3. Approximately what percentage of your revenues comes from international sales?

Less than 20%

20-40%

40-60%

60-80%

More than 80%

Don’t know

Example 4. How many employees work in your HR Department?

We don’t have an HR Department

1-5

6-10

11-20

21-50

More than 50

Don’t know/Not sure

Now let’s look at an exception to the second guideline for count data. When the respondent is providing an approximation or an estimate, then there is no need to provide non-overlapping choices. See examples 5 and 6.

Example 5. Approximately how many employees work at your company?

1-100

100-500

500-1,000

1,000-10,000

10,000+

Don’t know/Not sure

Example 6. What is your approximate family income?

< $30,000

$30,000 – $50,000

$50,000 – $100,000

$100,000 – $150,000

$150,000 – $200,000

$200,00 – $250,000

> $250,000

Don’t know/Not sure

For these last two examples the overlap by a single dollar or a single person is of no consequence and including ranges down to a single dollar or person would feign spurious accuracy.

Conclusion

There you have it — a simple best practice to keep in mind in order to put yourself in a position in which you are receiving informative, actionable survey data.

The next time you are creating multiple choice questions, be sure to keep this concept top of mind so that your resulting survey data can inform your business decisions.